Reviewing “Interlocking Directorates”: Clarifying the construct to understand the effect discrepancies across interlock studies

This review argues that the concept of interlocking directorate is theoretically eclectic, covering multiple subthemes whose relevance depends on global institutional variations. Against this background, this review seeks to clarify the construct of interlocking directorates and outline how the concept has been defined in empirical research. By systematically reviewing a sample of 146 papers testing the statistical effects of interlocks on firms’ financial performance and political cohesion, respectively, this study finds that the boundary conditions of interlocking directorates are often undefined and that the operationalizations of interlocking directorates are so diverse that they are not consistent in what they measure, but capture different aspects of the same phenomenon. To assist future empirical research on interlocking directorates, ensuring conceptual clarity and within-paper validity, a roadmap connecting conceptual constructs, boundary conditions, and empirical measurements is provided.